This course introduces a number of basic scientific principles underpinning the methodology of cooking, food preparation and the enjoyment of food. All topics covered have a strong basis in biology, chemistry, and physics application. Among others, they include the consumption of cooked food, the physiological and evolutionary implication of the senses, geographic and cultural influences on food, and the rationale behind food preparation. We will also discuss issues such as coupling of senses to improve sense stimulation; altering flavor by chemical means; and modification of the coloration to improve the appearance of dishes. Following the video demonstrations of the scientific principles of cooking, you will learn to recognize the key ingredients and their combinations for preparing good healthy food. At the end of this course, you will be able to:
- appreciate the scientific basis of various recipes;
- develop your own recipes by integrating some of the scientific principles into new dishes;
- recognize the influence of the material world on human perception from the different senses;
- appreciate the art of integrating science into cooking and dining.
Important Note: This course is not designed for people with special dietary needs such as vegetarian, diabetic, and gluten-free diets. If you feel uncomfortable with any part of the assignments or activities of this course, you can substitute some of the ingredients or ask friends and family members to help with the tasting of your assignments. Alternatively, you may skip that specific assignment provided that you have fulfilled all other qualifying requirement to pass the course.
Course Overview video: https://youtu.be/H5vlaR0_X2I

Enseigné par

King L. Chow

Professor

Lam Lung Yeung

Associate Professor

Transcription

Here is all the components of the meat. In fact, meat's composed of several essential elements. Like for example, water, protein, fat, carbohydrates, vitamins, minerals, and various organic compounds. So all these components, they are different. For example, like water, it's actually the most abundant component inside the meat, actually normally occupies about 75%. The next thing would be the protein, or we normally call it muscle fiber, about 20%, and then the rest mostly will be the fat and also carbohydrate. In the following, I'm going to show you different types of meat. They have different ratio of all these components. Like for example, for beef, it has 80% of protein but about 22% of fat. When we look at pork, you can see the percentage of water is actually lower compared to the beef, but however, in terms of fat, it occupies about 45%. If we look at chicken, it contains quite a lot of components of water, 85% to 65%, whereas we have the highest percentage of protein, but a lowest percentage of fat. From this table, what you can know is which meat is the healthiest, which you are going to take. I guess everybody knows, it has to be chicken. Whereas pork, since it contains really high percentage of fat, this, I don't think, is healthy compared to beef and also chicken. So if you are actually on diet, I recommend to not to take to much pork. Now, in terms of the muscle structure, in fact, the muscle is actually composed of lots of so-called muscle fibres. And between the fibre, and the fibre bundle, there's connective tissue in connecting all the muscles together. And when all the connective tissue combine together, it actually becomes a tendon. The tendon is where the muscle connects to the bones. So normally this is so-called the muscle structure. Now I'll show you a diagram, actually shows you here's the muscle. In fact, it contains different muscle bundles. And inside each muscle bundle, we have muscle fiber. And all these muscle bundles are connected with some of the connective tissue. And then, eventually, it all goes together to a tendon and then it connects with bone. For a muscle fibre, it actually has a diameter about 50 to 100 micrometer. But however, for this meat fibre, actually it's composed of really fine filament, so called myofibril and this myofibril has a diameter of only one to two micrometers. It's very small, it's being packed together inside a so-called meat fibre. But you make ask the question, how does the muscle actually undergo relaxation and also contraction? So in each muscle fibre, it's actually composed of two different types of protein, the so-called actin and also the myosin. The blue color, in fact, is the actin and the red color is the myosin. So when the two proteins actually are able to move around like, for example, in terms of structure. So when the muscles contract, what you can see, there's two layers. The actin starts to move towards together with the action of myosin. So, you may imagine how the myosin and also the actin move together, it's actually by the action of so-called attachment and detachment of the actin-myosin, eventually they're able to move gradually towards each other. So in the couple of slides, I'll going to tell you how this muscle can move together, but you might ask a question, where is the energy coming from, why are they able to contract and relax? Here's a schematic stylegram actually shows how the two things come together. But I'm going to tell you one thing is, where is the energy coming from from? I'll try to introduce a term, the so-called ATP. So the full name of ATP is so-called adenosine triphosphate. It's a molecule so-called an energy currency. But you wonder why it's called a energy currency. So in this molecule, why's it called ATP. It's T stand for tri, tri means three. So from this stylegram, what you can see, in fact, it contains three phosphates, one, two, three, right? Three phosphate atoms, so it's called adenosine triphosphates, which represents, more or less, a high-energy level. However, this molecule can be decomposed into a lower-energy level state, called ADP. D stands for diphosphate. You can see from this diagram, this compound, in fact, decomposed. If fact, one phosphate, one inorganic phosphate actually detached from the whole molecule to form a relatively low-energy. This diagram shows how ATP interacts with the myosin head. In a rest state, the myosin has cross-linked with the active molecule. When the ATP molecule comes to the myosin head, it combines with the myosin head which we saw in the detachment of the myosin head away from the actin protein. When the myosin head moves away from the actin protein, the ATP starts to decompose and becomes ADP and also inorganic phosphate. From this diagram, what you can see, the ATP molecules start to decompose, become the ADP molecule together with a inorganic phosphate. With the ATP actually on the myosin head, the myosin head can be recombined to the actin protein again with the result of the release of the ATP molecule and also inorganic phosphate. So from this diagram, what you can see, the two molecules actually release from the myosin head. And with the result of the reattachment of the myosin head to the actin protein. So for this kind of detachment and attachment, a sliding motion of actin results and the attachment of this course-bridge between the actin and the myosin head, we saw the release of the ADP and also the phosphate atom. This schematic stylegram shows how the two things work. The inner layer actually represents the myosin, whereas the upper two actually represents the actin. So, when the so-called detachment and attachment action keeps on going, it actually results, the two actin actually goes together and then move to the center. So this actually tells how the muscle actually contracts. And for the contraction of this muscle fiber, in fact, it produces a power stroke, like this. And then when the muscle actually relaxes, it actually goes back to original state. But you might ask, what happens when an animal is slaughtered? For example, like this case, when the animal has died, basically there's no blood circulation. In other words, the molecule cannot attain the ATP anymore. So it results in a kind of locked position. That explains why normally when an animal dies, their muscle is really tough. We call this process rigor mortis.